Ou Sarin was 43 when both his legs were blown off. You have probably never heard of the war in which it happened. Look in the record books and you won't find anything about minefields being laid in Cambodia as recently as 1991. It was just one of those small local wars – between a group of rebels whose cause was lost in the midst of history – and government troops.

When the fighting was over in the fields where Mr Sarin grew maize and rice, the departing government soldiers told him: "Don't worry. All the mines have been 100 per cent cleared." But they hadn't.

It took 24 hours for his friends to carry him from the village of Kamnop to the nearest hospital in Takeo province. By the time he got there the doctor had no other choice than to amputate both his legs, one below the knee, the other above. Because he also had severe malaria he was kept in hospital for two months. He told his relatives to sell all his oxen and his wife sold her gold jewellery. Between them they raised $2,500 (£1,700). It just about paid the hospital bill.

He returned to his village in a battered old wheelchair given to him by the hospital. "When I got back there was a big change in how everyone treated me," he recalls. "No one wanted to speak to me. I was shunned. Everyone treated me as a burden."

Worse than the ostracism was the mockery. The villagers gave him the cruel nickname "the Frog" because of his posture. "They said that all frogs were good for was eating." Cambodian drinkers like grilled frogs to eat while drinking alcohol. The disdain became so bad that, combined with his sense of shock at the condition in which he now found himself, he decided to kill himself. "I would have done it many times but my wife was strong and counselled me and built the strength in me."

For the first year his wife ran the farm. "All I could do was help clean the rice after the harvest and put it in sacks." But he was determined to keep on. From his wheelchair he began to plant trees – 20 mango, 15 jack fruit, 30 lemon trees. But, despite all his efforts, he could not make a success. Then, four years after the explosion which took his legs, an aid worker came to the village and suggested that he go away to a rehabilitation centre for people with disabilities, to get some training. He learnt how to repair motorbikes and afterwards returned to Kamnop to set up his own one-man business.

"I had a lot of customers but they would only come to me when they had no money," he says. "They asked for credit, but they never paid the bills. They felt they could cheat me because they knew that I would not be able to catch them to get the money."

For Mr Sarin the turning point came with the arrival of workers funded by Action on Disability and Development (ADD) which is one of the charities being supported by this year's Independent Christmas Appeal. They taught him that he had rights under Cambodian law as a disabled person. ADD also offered to fund a scheme which had been germinating at the back of his mind since he first went to the training centre. "Until I went there I had never met another disabled person. I thought I must be the only one who had to live like this," he recalls. "I developed a plan to go to all the villages around Kamnop to find out whether there were other disabled people like me."

But he had lacked the confidence to set out to fulfil the plan. ADD gave him that confidence: "My son began to give me a lift on his motorbike to other villages." ADD expanded Mr Sarin's initiative and three other disabled people joined him in what it now calls the "counterpart" programme. "We now have joined up 294 disabled people in three different communes in 22 self-help groups," he says.

That work has been replicated elsewhere, thanks to ADD. The counterpart programme now reaches hundreds of disabled people – and educates local officials, teachers, council staff and community and religious leaders about the rights of disabled people. The status this has given Mr Sarin with the local authorities has rubbed off on the people in his village. "Today I am treated with respect. People have listened to me for the first time. They have begun to think what life must be like for someone with a disability. Attitudes have really changed."